User`s Manual
Contents
1. 4800 baud rate other rate optional 8 bits data 1 stop bit no parity 1 PPS Pulse pulse duration Is Time reference at the pulse positive edge Synchronized to GPS time 1 us 2 2 Environmental Characteristics Operating temperature range Storage temperature range 40 C to 85 C 45 C to 100 C SR 90 User s Manual V1 1 pacA ma SR 90 Manual V1 0 2 3 Physical Characteristics Top view Bu 3 2m 10987654321 Top view 7 Y Bo 8 1 20 212273 2425262728 29 30 Pin Assignment Name 1 VCC DC Supply Voltage input RXA TXA i i 4567 TXB RXB IOOI Serial port A Serial port A Serial port B Serial port B GPIO14 Fs tor o General purpose I O A 11 16 GND_A Analog Ground 18 GND_A Analog Ground 19 V_ANT_IN Active Antenna Bias voltage 20 VCC_RF Lao Supply Antenna Bias voltage 21 22 YBa Backup voltage supply Reset Active low Reset 23 GPIO10 General purpose I O GPIO1 T O 24 25 26 GPIO5 T O GPIOO T O General purpose I O General purpose I O General purpose T O support continuous power mode only 27 GPIO13 So GeneratpurposetO General purpose I O GPIO15 T O O oe 28 29 30 PPS GND General purpose I O One pulse per second Digital Ground SR 90 User s Manual V1 1 pacA ma SR 90 Manual V1 0 Definition of Pin assignment VCC This is the main DC supply for a 3 3V 5 DC input power module board GND GND provides the ground for digital part Boot select Set this pin to high for pr2. Units N N knots Speed 0 2 km hr Speed Units K K km hour Mode A Az Autonomous D DGPS E DR Checksum 23 lt CR gt lt LF gt Message terminator 1 SiRF does not support magnetic declination All course over ground data are geodetic WGS84 directions 2 Fields marked in italic red apply only to NMEA version 2 3 and later in this NMEA message description 16 SR 90 User s Manual V1 1 pacA ma GPZDA This message transfers UTC Time and Date GPZDA 181813 14 10 2003 00 00 4F The GPZDA message format is shown below SR 90 Manual V1 0 Following is an example Field Example Unit Notes Message ID GPZDA ZDA protocol header UTC Time 181813 Either using valid IONO UTC or estimated from default leap seconds UTC Day 14 01 to 31 day of month UTC Month 10 01 to 12 UTC Year 2003 1980 to 2079 Local zone hours 00 Offset from UTC set to 00 Local zone minutes 00 Offset from UTC set to 00 Checksum 4F lt CR gt lt LF gt Message terminator All Rights Reserved 17 SR 90 User s Manual V1 1
3. 11 12 13 14 15 16 18 shall be connect to analog ground The GND pin 2 gt 10 30 connect to digital ground 2 Serial Interface The Serial interface pin RXA TX1 TXB_ gt RXB is recommended to pull up 10K Q It can increase the stability of serial data 3 Backup Battery It s recommended to connect a backup battery to V_BAT In order to enable the warm and hot start features of the GPS receiver If you don t intend to use a backup battery connect this pin to GND or open If you use backup battery shall need to add a bypassing capacitor 10uF at V_bat trace It can reduce noise and increase the stability 4 Antenna Connecting to the antenna has to be routed on the PCB The transmission line must to controlled impedance to connect RF_IN to the antenna or antenna connector of your choice 5 Active antenna bias voltage The Vcc_RF pin pin 20 is providing voltage 3 3V If you use active antenna you can connect this pin to V_ANT_IN pin pin 19 to provide bias voltage of active Mechanical Layout SR 90 User s Manual V1 1 29 420 2 24 4 25 4 0 2 rene SR 90 Manual V1 0 eS a OS SR 90 User s Manual V1 1 pacA ms SR 90 Manual V1 0 Appendix Software Specifications NMEA Protocol The interface protocol is based on the National Marine Electronics Association NMEA interface specification namely the NMEA 0183 standard The unit is capable of supporting the following NMEA messag
4. 12 pacA ms SR 90 Manual V1 0 GPGSV This message transfers information about satellites in view The GPGSV message structure is shown below Each record contains the information for up to 4 channels allowing up to 12 satellites in view In the final record of the sequence the unused channel fields are left blank with commas to indicate that a field has been omitted Following is an example GPGSV 2 1 07 07 79 048 42 02 51 062 43 26 36 256 42 27 27 138 42 71 GPGSV 2 2 07 09 23 313 42 04 19 159 41 15 12 041 42 41 The GPGSV message structure is shown below Field Example Unit Notes Message ID GPGSV GSA protocol header Number of messages 2 Number of messages maximum 3 Message number 1 Sequence number range 1 to 3 Satellites in view 07 Number of satellites currently in view Satellite ID 07 Channel 1 ID range 1 to 32 Elevation 79 degree Elevation of satellite maximum 90 Azimuth 048 degree Azimuth of satellite range 0 to 359 SNR C No 42 dBHz Range 0 to 99 null when not tracking Satellite ID 02 Channel 2 ID range 1 to 32 Elevation 51 degree Elevation of satellite maximum 90 Azimuth 062 degree Azimuth of satellite range 0 to 359 SNR C No 43 dBHz Range 0 to 99 null when not tracking Satellite ID 26 Channel 3 ID range 1 to 32 Elevation 36 degree Elevation of satellite maximum 90 Azimuth 256 degree Azimuth of satellite range
5. 0 to 359 SNR C No 42 dBHz Range 0 to 99 null when not tracking Satellite ID 27 Channel 4 ID range 1 to 32 Elevation 27 degree Elevation of satellite maximum 90 Azimuth 138 degree Azimuth of satellite range 0 to 359 SNR C No 42 dBHz Range 0 to 99 null when not tracking Checksum 71 lt CR gt lt LF gt Message terminator 1 Depending on the number of satellites tracked multiple messages of GSV data may be required SR 90 User s Manual V1 1 13 pacA ma SR 90 Manual V1 0 GPMSS This message transfers information about radio beacon signal to noise ratio signal strength frequency etc Following is an example GPMSS 55 27 318 0 100 1 57 The GPMSS message format is shown below Field Example Unit Notes Message ID GPMSS MSS protocol header Signal Strength 55 dB SS of tracked frequency Signal to Noise Ratio 27 dB SNR of tracked frequency Beacon Frequency 318 0 kHz Currently tracked frequency Beacon Bit Rate 100 Bits per second la jA hs foal Te Checksum 257 lt CR gt lt LF gt Message terminator 1 Fields marked in italic red apply only to NMEA version 2 3 and later in this NMEA message description SR 90 User s Manual V1 1 14 bac ms GPRMC This message transfers recommended minimum specific GNSS data example SR 90 Manual V1 0 Following is an GPRMC 161229 487 A 3723 2475 N 12158 3416 W 0 13 309 62 120
6. 598 10 The GPRMC message format is shown below Field Example Unit Notes Message ID GPRMC RMC protocol header UTC Time 161229 487 hhmmss sss Status A A Data valid or V Data invalid Latitude 3723 2475 ddmm mmmm N S Indicator N N north or S south Longitude 12158 3416 ddmm mmmm E W indicator W E east or W west Speed over ground 0 13 knot Speed over ground Course over ground 309 62 degree Course over ground Date 120598 ddmmyy current date Magnetic variation degree Not used Mode A A Autonomous D DGPS E DR Checksum 10 lt CR gt lt LF gt Message terminator 1 SiRF does not support magnetic declination All course over ground data are geodetic WGS84 directions 2 Fields marked in italic red apply only to NMEA version 2 3 and later in this NMEA message description 15 SR 90 User s Manual V1 1 pacA ma GPVTG SR 90 Manual V1 0 This message transfers velocity course over ground and ground speed Following is an example GPVTG 309 62 T M 0 13 N 0 2 K A 23 The GPVTG message format is shown below Field Example Unit Notes Message ID GPVTG VTG protocol header Course true 309 62 degree Measured heading Reference T T true heading Course magnetic degree Measured heading Reference M M magnetic heading Speed 0 13 knot Speed in knots
7. e formats specifically developed and defined by SiRF NMEA M rea Format Direction Prefix GPGGA Time position and fix type data Out GPGLL Latitude longitude time of position fix and status Out GPGSA GNSS DOP and active satellites Out GPGSV Satellites in view Out GPMSS Radio beacon signal to noise ratio signal strength Out frequency etc GPRMC Recommended minimum specific GNSS data Out GPVTG Speed and course over ground Out GPZDA Date and time Out General NMEA Format The general NMEA format consists of an ASCII string commencing with a character and terminating with a lt CR gt lt LF gt sequence NMEA standard messages commence with GP then a 3 letter message identifier The message header is followed by a comma delimited list of fields optionally terminated with a checksum consisting of an asterix and a 2 digit hex value representing the checksum There is no comma preceding the checksum field When present the checksum is calculated as a bitwise exclusive of the characters between the and Asan ASCII representation the number of digits in each number will vary depending on the number and precision hence the record length will vary Certain fields may be omitted if they are not used in which case the field position is reserved using commas to ensure correct interpretation of subsequent fields SR 90 User s Manual V1 1 pac A ma SR 90 Ma
8. nsfers geographic position latitude longitude and time Following is an example GPGLL 3723 2475 N 12158 3416 W 161229 487 A A 41 The GPGLL message structure is shown below Field Example Unit Notes Message ID GPGLL GLL protocol header Latitude 3723 2475 ddmm mmmm N S Indicator N N north or S south Longitude 12158 3416 dddmm mmmm E W indicator W E east or W west UTC Time 161229 487 hhmmss sss Status A A Data valid or V Data invalid Mode A A Autonomous D DGPS3S E DR Only present in NMEA version 3 00 Checksum 41 lt CR gt lt LF gt Message terminator SR 90 User s Manual V1 1 11 pacA ms SR 90 Manual V1 0 GPGSA This message transfers DOP and active satellites information Following is an example GPGSA A 3 07 02 26 27 09 04 15 1 8 1 0 1 5 33 The GPGSA message structure is shown below Field Example Unit Notes Message ID GPGSA GSA protocol header M Manual forced to operate in selected Mode A 2D or 3D mode A Automatic switching between modes 1 Fix not available Mode 3 2 2D position fix 3 3D position fix Satellites Used 07 SV on channel 1 Satellites Used 02 SV on channel 2 Satellites Used SV on channel 12 PDOP 1 8 HDOP 1 0 VDOP 1 5 Checksum 33 lt CR gt lt LF gt Message terminator 1 Satellites used in solution SR 90 User s Manual V1 1
9. nual V1 0 GPGGA This message transfers global positioning system fix data Following is an example GPGGA 161229 487 3723 2475 N 12158 3416 W 1 07 1 0 9 0 M 0000 18 The GPGGA message structure is shown below Field Example Unit Notes Message ID GPGGA GGA protocol header UTC Time 161229 487 hhmmss sss Latitude 3723 2475 ddmm mmmm N S Indicator N N north or S south Longitude 12158 3416 dddmm mmmm E W indicator W E east or W west 0 Fix not available or invalid 1 GPS SPS mode fix valid Position Fix Indictor 1 2 Differ GPS SPS mode fix valid 3 5 Not supported 6 Dead Reckoning Mode fix valid Number of satellites used to calculate fix Satellites Used 07 Range 0 to 12 HDOP 1 0 Horizontal Dilution of Precision MSL Altitude 9 0 Meter Altitude above mean seal level Units M Meter M stands for meters Geoid Separation Meter Separation from Geoids can be blank Units Meter M stands for meters Age of Diff Corr Second Agein seconds Blank Null fields when DGPS is not used Diff Ref Station ID 0000 Checksum 18 lt CR gt lt LF gt Message terminator 1 Only apply to NMEA version 2 3 and later in this NMEA message description 2 SiRF does not support geoid corrections Values are WGS84 ellipsoid heights SR 90 User s Manual V1 1 10 pacA ma SR 90 Manual V1 0 GPGLL This message tra
10. ogramming flash RXA This is the main receiver channel and is used to receive software commands to the board from SIRFdemo software or from user written software PS Pull up if not used RXB This is the auxiliary receiving channel and is used to input differential corrections to the board to enable DGPS navigation PS Pull up if not used TXA This is the main transmitting channel and is used to output navigation and measurement data to SikFdemo or user written software TXB For user s application not currently used RF_ON This pin indicates state of RF voltage RF_IN This pin receiver signal of GPS analog due to the RF characteristics of the signal the design has to certain criteria The line on the PCB from theantenna or antenna connector has to be a controlled microstrip line at 50Q V_ANT_IN This pin is reserved an external DC power supply for active antenna If using 3 0V active antenna pin 19 has to be connected to pin 20 If using 3 3V or 12V active antenna this pin has to be connected to 3 3V or 5Vpower supply VCC_RF This pin provides DC voltage 3 0 for active antenna Reset This pin provides an active low reset input to the board It causes the board to reset and start searching for satellites If not utilized it may be left open PPS This pin provides one pulse per second output from the board which is synchronized to GPS time This is not available in Trickle Power mode Backup battery V_BAT SR 90 Use
11. pac ms SR 90 Manual V1 0 GPS Engine Board Manual SA G0 SiRF Star II V 1 1 DACA MA Made in Taiwan 2008 08 08 service dagamagps com www dagamagps com Free service hot line for mainland 400 820 1322 pacA ma SR 90 Manual V1 0 Specifications subject to change without prior notice Contents 1 Introduction isascdscdapascascecrcsaerscedeastadvcessncdieeeedannsdeviiomeaeseaenione 2 1 1 OVERVIEW cocescsiscsisioisojessesscr sioaren sse ressor seia ase e ria 2 1 2 Feat res ccicsisievanasses cacncksernassent aes ene E SESEO EENE sE EEE Ea 2 2 Technical Specifications eeseesesseseesessescesescesosseesesoescsseseesoeo 2 2 1 Electrical Characteristics sssssseesssssssocsssssesososssesossosssesessoo 2 2 2 Environmental Characteristics cccccccccscccccccccccccscccescsccescseees 3 2 3 Physical Characteristics scccsacecassvecerctaveterdaccccacerdineretescudceeeausens 4 Appendix Software Specifications sesesssosessesseoscsssososesssseseoe 9 SR 90 User s Manual V1 1 pacA ma SR 90 Manual V1 0 1 Introduction 1 1 Overview SR 90 GPS module is a high performance receiver module for the Global Positioning System GPS solution It combines SiRF Stari GPS single chip LNA circuit SAW filter oscillator crystal and regulators into a land grid array module The specified firmware is pre loaded into the built in 4 Mbit Flash memory of SR 90 for GPS application It can be ea
12. r s Manual V1 1 bacA ma SR 90 Manual V1 0 This is the battery backup input that powers the SRAM and RTC when main power is removed Typical current draw is 15uA Without an external backup battery the module engine board will execute a cold star after every turn on To achieve the faster start up offered by a hot or warm start a battery backup must be connected The battery voltage should be between 2 0v and 5 0v Without an external backup battery or super cap the TMP will execute a cold start after every power on To achieve the faster start up offered by a hot or warm start either a battery backup must be connected or a super cap installed To maximize battery lifetime the battery voltage should not exceed the supply voltage and should be between 2 5V and 3 6V With the super cap B1 installed and after at least ten minutes of continuous operation the data retention is about seven hours Note that even though all other components are rated at 30 to 85 deg C a typical super cap is specified over a temperature range of 25 to 70 deg C and a typical rechargeable Lithium battery is over 20 to 70 deg C GPIO Functions Several I Os are connected to the digital interface connector or custom applications Application Circuit vec 0 ohm microstrip line 2 ACTIVE ANT 1 SR 90 User s Manual V1 1 4 ZN A acA ma SR 90 Manual V1 0 1 Ground Planes SR 90 GPS receiver needs two different ground planes The GND_A pin
13. sily embedded into portable devices for GPS wireless communication 1 2 Features SIRF starI high performance GPS Chip Set Very high sensitivity Tracking Sensitivity 159 dBm Extremely fast TTFF Time To First Fix at low signal level Compact size 25 4mm 25 4 mm 3 3mm suitable for space sensitive application One size component easy to mount on another PCB board Support NMEA 0183 and SiRF binary protocol 2 Technical Specifications 2 1 Electrical Characteristics 2 1 1 General Frequency L1 1575 42 MHz C A code 1 023 MHz chip rate Channels 20 channels all in view tracking 2 1 2 Sensitivity Tracking 159 dBm typical 2 1 3 Accuracy Open Sky Position 10 meters 2D RMS 5 meters 2D RMS WAAS enabled Time 1 microsecond synchronized to GPS time 2 1 4 Datum Default WGS 84 SR 90 User s Manual V1 1 D Daca ms SR 90 Manual V1 0 2 1 5 Acquisition Rate Open Sky Hot start Warm start Cold start Reacquisition 2 1 6 Dynamic Conditions Altitude Velocity Acceleration Jerk 2 1 7 Power Main power input Supply Current 2 1 8 Serial Port Electrical interface Protocol support Default NMEA 2 1 9 Time 1 sec average 38 sec average 42 sec average 0 1 sec average 18 000 meters 60 000 feet max 515 meters sec 1000 knots max Less than 4 G 20 meters sec max 3 3 5 VDC input 68mA Continuous mode TTL level NMEA 0183 SiRF Binary GGA GSA GSV RMC GLL VTG and ZDA optional
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